Image signal processing apparatus for setting a noise component attenuation characteristic

a signal processing and noise component technology, applied in the field of suppressing noise, can solve the problems of increased noise of each shot due to a dark current, marked and detection of the rise and fall of each shot noise, so as to reduce the deterioration of image quality and increase the exposure time

Inactive Publication Date: 2010-11-30
SEMICON COMPONENTS IND LLC
View PDF10 Cites 7 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0007]The present invention has been made to solve the above problems, and an object of the invention is therefore to suppress image quality deterioration due to an increased exposure time in an image signal processing apparatus for processing an image signal that is generated by an image pickup device.

Problems solved by technology

And there is a problem that the shot noise due to a dark current becomes higher as the exposure time becomes longer.
Further, in the outline emphasis processing, the rise and fall of each shot noise are also detected and subjected to the outline emphasis.
Marked deterioration in image quality is caused by enhanced shot noise due to an increased exposure time.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Image signal processing apparatus for setting a noise component attenuation characteristic
  • Image signal processing apparatus for setting a noise component attenuation characteristic
  • Image signal processing apparatus for setting a noise component attenuation characteristic

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0016]First, basic configurations of an image signal processing apparatus according to a preferred embodiment of the present invention will be outlined.

[0017]A first basic configuration of the image signal processing apparatus according to the embodiment of the invention comprises a filter circuit for attenuating a noise component included in an image signal, a noise component attenuation characteristic of the filter circuit being variable; and a filter control circuit for setting the attenuation characteristic of the filter circuit in accordance with an exposure time that is employed by an image pickup device in generating the image signal.

[0018]One example of the image signal processing apparatus is such that the filter circuit is a digital low-pass filter and the filter control circuit changes a cutoff frequency of the digital low-pass filter by changing tap coefficients thereof.

[0019]Another example of the image signal processing apparatus is such that the filter circuit has a m...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

An image signal is input to two LPFs having different transmission characteristics. A selector chooses one of outputs of the respective LPFs and delivers the chosen output to a gamma correction circuit. The switching of the selector is controlled by a filter control circuit. In the filter control circuit, a comparator compares an exposure time E of a current frame with a threshold value R. The selector is controlled so as to select an output of one of the LPFs that has a lower cutoff frequency and a greater noise component elimination effect than the other LPF does if the exposure time E is longer than or equal to the threshold value R.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The priority application Number JP2004-015046 upon which this patent application is based is hereby incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to an image signal processing apparatus for processing an image signal that is generated by an image pickup device. In particular, the invention relates to a technique for suppressing noise that depends on the exposure time of an image pickup device.BACKGROUND OF THE INVENTION[0003]Image pickup apparatuses such as digital cameras can produce an image signal having a proper signal level by adjusting the exposure time automatically or manually in accordance with the brightness of an object.[0004]FIG. 1 is a block diagram showing the configuration of a conventional image signal processing apparatus for processing an image signal that is generated by an image pickup device. An image signal that is output from an image pickup device 2 such as a CCD (charge-couple...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Patents(United States)
IPC IPC(8): H04N5/217H04N5/228H04N5/208H04N5/235H04N1/38H04N1/40H04N1/409H04N5/213H04N5/225H04N5/232
CPCH04N1/4092G06T5/003
Inventor TAKAHASHI, TATSUYANAKAI, TOMOMICHINAKAKUKI, TOSHIO
Owner SEMICON COMPONENTS IND LLC
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap